Lubricating composition



United States Patent 3,287,266 LUBRICATING COMPOSITION Derek Southern,Heswall, Wirral, Francis H. Waight, Little Sutton, Wirral, and AlexanderC. B. MacPhail, Eastham, Wirral, England, assignors to Shell OilCompany, New York, N.Y., a corporation of Delaware No Drawing. FiledMar. 30, 1964, Ser. No. 355,949

Claims priority, application Great Britain, Apr. 23, 1963, 15,953/63Claims. (Cl. 25246.7)

This invention relates to lubricating oil compositions having improvedextreme-pressure properties. In particular, this invention concernssynthetic lubricants containing certain diaryl haloalkyl phosphates.

In recent years, various types of synthetic lubricants have becomeavailable to satisfy stringent requirements not met by conventionalmineral oils. For example, a major application for synthetic lubricantshas been in aircraft turbine engines, which must perform at temperaturesas low as -65 F., and maintain stability at tem peratures as high as 400to 500 F.

One of the most diflicult problems encountered in the formulation ofsynthetic lubricants is imparting extremepressure properties to the oil.Various additives have been proposed for making these compositionssuitable for lubrication at the high pressures, temperatures, and speedsnormally encountered in their use. Although some com pounds havesuccessfully contributed good antiwear characteristics, few have alsomet the equally important requirements of low sludge and depositformation and thermal stability.

It is an object of the present invention to provide a lubri eatingcomposition with excellent extreme-pressure properties which isresistant to sludge and deposit formation and which :has good thermalstability.

It has now been discovered that certain diaryl haloalkyl phosphatesimprove the extreme-pressure properties of lubricating oils to asubstantially greater extent than was possible With other known EPagents. Lubricants of the invention contain 0.1 to 10%, preferably 2 to6% by weight, of a diaryl haloalkyl phosphate of the formula wherein Ris monoto di-nuclear aryl which is substituted with from 0 to 5,especially -0 to 2 alkyl groups having from 1 to 10 carbons; X is achalcogen having an atomic number from 8 to 16; R is nonto di-alkylmethylene wherein alkyl has 1 to 4 carbons; n is an integer from 1 to 6,preferably 1 to 3, especially 1; Y is nonto perchloroalkyl having 1 to 2carbons; and Z is monoto trichloromethyl. Preferred com-positionscomprise a synthetic base with one or more additives of the inventionwherein the above formula one or more of the following is true: R is aphenyl group substituted with from 0 to 2 alkyl groups having 1 to 10carbons, X is a chalcogen having an atomic number from 8 to 16 (i.e.,oxygen or sulfur), R is methylene, n is 1, Y is nonto tri-chloroalkylhaving 1 to 2 carbons (i.e., CH CH Cl, ChCl CCl C2H5, C H4Cl, C H Cl 0rC H Cl and Z is monochloromethyl.

Examples of additives of the invention are phenyl naphthyl5,5-dichloropentyl 4,4-bis(chloromethyl) phosphate; octylphenylhexyl-phenyl 7,7,7-trichloroheptyl -6-chloromethyl 6-dichloromethylphosphorothionate; (dioctyl) phenyl phenyl 3,3-bis(chloromethyl)4-chlorobutyl phosphate; dioctylphenyl 2,2-bis(trichloromethyl)3,3-dichl0ropropyl phosphorothionate; diphenyl 3,3-bis (chloromethyl)4,5-dichloropentyl phosphate.

Particularly preferred diaryl haloalkyl phosphates are diphenyl 2,2 bis(chlorornethyl) 3 chloropropyl phosphate; diphenyl 2,2 bis(chloromethyl)3-chloropropyl phosphoro thionate; dioctylphenyl-2,2-'bis (chloromethyl)3-chloropropyl phosphate; and dioctylphenyl-2,2-bis(chloromethyl)-3-chloropropyl phosphorothionate.

The additives of the invention may be used to impart EP properties toeither synthetic or mineral oils, but are preferably used in syntheticester bases. The ester lubricant bases are preferably aliphaticcarboxylic acid esters. These may be esters of a rn'onohydric aliphaticalcohol having from 3 to 18 carbon atoms with a monobasic aliphatic acidhaving from 4 to 18 carbon atoms, for example, isodecyl pelargonate Afurther class of aliphatic carboxylic acid esters which may be used isthe aliphatic esters of monobasic carboxylic acids having 4 to 18 carbonatoms and a glycol having 4 to 20 carbon atoms, for example esters ofneopentyl glycol, Z-butyl-Z-ethyl-propanediol and dipropylene glycolwith heptylic acid, n-octoic acid, and pelargonic acid.

A particularly preferred class of aliphatic carboxylic acid esters foruse in the lubricating oil compositions of the invention is thealiphatic diester of dibasic carboxylic acids having from 6 to 20 carbonatoms and monohydric alcohols having from 1 to 12 carbon atoms, forexample esters of adipic acid, pimelic acid, suberic acid, azelaic acidand sebacic acid with lauryl alcohol, heptyl alcohol, octyl alcohol andnonyl alcohol. Particularly preferred aliphatic diesters of dicarboxylicacids are those derived from monohydric alcohols having a branchedchain, for example Z-ethyl hexanol and especially those having nohydrogen on the beta carbon atom, for example 2,2-dimethyl pentanol,2,2,4-trimethyl pentanol, 2,2,3-trimethyl pentanol, 2,2-dimethylhexanol,and 2-methyl-2-ethyl hexanol.

As examples of other aliphatic carboxylic acid esters which may be usedthere are mentioned aliphatic esters of monocarboxylic acids having from3 to 10 carbon atoms, for example, propionic acid, butyric acid, valericacid, capric acid, caprylic acid, lauric acid and pelargonic acid andpolyols, for example, pentaerythritol, dipentaerythritol andtrimethylolpropane.

Examples of such esters are pentaerythrityl butyrate, pentaerythrityltetrabntyrate, pentaerythrityl tetravalerate, pentaerythrityltetracaproate, pentaerythrityl dibutyratedicaproate, pentaerythritylbutyratecaproate divalerate, pentaerythrityl butyrate trivalerate,pentaerythrityl butyrate tricaproate, pentaerythrityltributyrate-caproate, mixed C saturated fatty acid esters ofpentaerythritol, dipentaerythrityl hexavalerate, dipentaerythritylhexacaproate, dipentaerythrityl hexaheptoate, dipentaerythrityl hexacaprylate, dipentaerythrityl tributyratecaproate, dipentaerythrityltrivalerate trinonylate, dipentaerythrityl mixed hexaesters of C C fattyacids, and trimethylolpropane heptylate.

To illustrate the improved lubricating oil compositions of the presentinvention the compositions as shown in Table I (Examples IV-VII) weremade, tested and compared against the base oil (Example I) and acomposition containing the same amounts of a known extreme pressureadditive (Examples 11 and III).

These compositions were tested for their load-carrying capacity on anI.A.E. Gear Rig as described in the Institute of Petroleum Method 166/60T using BSS-EN 34 steel gears and operating at an oil temperature ofeither 60 C. or C. The mean failure loads at 2000 rpm. and 6000 r.p.m.at both the aforementioned temperatures were determined and recorded inTable II.

TABLE I Composition of Example (percent Wt.) I

Di(isooetyl azelate) Aroclor 1254 (chlorinated diphenyl)Diphenyl-2,2-bischloromethyl-IS-chloropropyl Dioetylphenyl-2,2-bis-chloromethyl-3-ehloropropy] phnsphnh:

3 ,7-dioctyl phenoi'hiarinp Phenyl-alphanaphthylamine 5-1nethylbenzotriazole, p.p.m Azelaic acid Silicone MS 200/12,500, ppm

TABLE II Example I II III VI VII I.A.E. Sending Load (lbs):

2,000 r.p.m.:

Sum or Scufling Load (lbs) /1io1 R0 X wherein R and X are as definedabove.

The following preparations are illustrative of the method of preparingthe novel phosphates for use as extremepressure additives in thecompositions of the present invention.

Preparation 1.DiphenyZ-2,2-bis(chloromelhyl) -3- chloropropyl phosphateChlorine, percent wt 53.9 (theory 55.6% wt.).

Hydroxyl value (rneq./ g.) 5.12 (theory 5.22).

100 grams (0.52 mole) of 2,2-bis(chloromethyl)-3-chloropropanol, 134grams (0.5 mole) of diphenyl phosphorochloridate and 50 grams (0.63mole) of pyridine are placed in a flask and shaken. The mixturetemperature slowly rises and thus the reaction fiask is water-cooleduntil the reaction ceases. Toluene (50 ml.) is added and the resultingmixture is refluxed for four hours. When cool, the reaction mixture isfurther diluted with 50 ml. light petroleum spirit (B.P. 100-120 C.),benzene (50 ml.) and water (50 ml.). washed successively with water,dilute sodium bicarbonate The resulting organic layer is solution andWater until neutral. Water and organic solvent are removed bydistillation and the final product is distilled under reduced pressureand on cooling this product crystallizes to a White solid which isdiphenyl-2,2-bis (chloromethyl) -3-chloropropyl phosphate and which gaveon analysis:

Acid value Nil. Free chloride Nil. Chlorine (percent wt.) 24.8 (theory25.1% wt.).

Preparation II.Dioctylphenyl-2,2-bis(chl0r0methyl)-3- chloropropylphosphate Distilled p-octyl phenol (116 g., 0.56 mole) and distilledphosphoryl chloride (43.2 g., 0.28 mole) are placed in a flask fittedwith a thermometer and a stirrer. The temperature of the reactionmixture is slowly increased to 228 C. over a period of 2 hours and somaintained for a further 2 hours. The resulting product is distilledthrough a 12" x Vigreux column which is lagged with a heating tape, andthe fraction boiling up to 240 C. at 15 mm. Hg pressure analyzed fordi-p-octyl phenyl phosphorochloridate. A sample of thephosphorochloridate prepared in this manner gave on analysis: Chlorine(percent wt.), 7.20 (theory 7.20% wt.).

27.6 grams (0.06 mole) of di-p-octylphenyl phosphorochloridate, 13.8grams (0.07 mole) of 2,2-bis(chloromethyl)-3-chloropropanol as preparedin Preparation I and 6 grams pyridine (0.08 mole) are placed in a flask,the contents shaken and the flask cooled. Toluene is added (50 ml.) andthe mixture is refluxed for four hours; two distinct layers are formedin the reaction flask. The product is diluted with ml. of a mixture oflight petroleum spirit (B.P. 100-120 C.) and benzene and is then washedwith water, dilute sodium bicarbonate solution and water until neutral.The solvent is then distilled. The residue, containing free chloride, isdiluted with toluene and the resulting solution is slurried withAmberlite IRA-400 ion exchange resin (activated by washing with NaOHsolution). After filtering, the solvent is removed by distillation,leaving an amber-colored liquid product which isdip-0ctylphenyl-2,2-bis(chloromethyl)-3-chloropropyl phosphate and whichhad the following analysis:

Acid value 0.7 mg. KOH/ g. Free chloride Nil. Chlorine (percent wt.)16.45 (theory 16.42% wt.).

The lubricating oil compositions of the present invention may alsocontain any of the known additives for aliphatic carboxylic acid esterlubricating oils, for example, thickeners, antioxidants, anti-lacqueringagents, anti-foaming agents, dyes, anti-corrosion agents, metaldeactivators and additional extreme-pressure additives if so desired.

Suitable thickeners are polyalkylene glycols and their monoor di-ethersand esters and the polymers of esters of acrylic or l-alkyl acrylicacids. Examples of antioxidants which may be used in the lubricating oilcompositions according to this invention are alkylated phenols, forexample 2,6-diter-tiary butyl-4-methyl phenol; alkylated bis phenols,for example, 4,4-methylene bis(2,6-ditertiary butyl phenol); aromaticamines, e.g., phenyl-ocnaphthylamine, phenyl-B-naphthylamine,.2,2'-dipyridylamine, diphenylamine and alkyl substituted derivativesthereof. An especially preferred class of antioxidants is thethiodiarylamines, for example, phenothiazine and 3,7- dioctylphenothiazine. Mixtures of antioxidants may also be used, particularlymixture containing a thiodiarylamine, e.g., a mixture of phenothiazineand phenyl-anaphthylamine.

Suitable anti-forming agents are the polydimethyl siloxanes havingviscosities from 100 to 100,000 centistokes at 25 C. Examples ofanti-corrosion agents and metal deactivators are benzotriaz-ole,S-methyl benzotriazole and low molecular weight dicarboxylic acids,e.g., azelaic acid, pimelic acid.

Other extreme-pressure additives which may be used if so desired are,for example, the chloronated dior polypheuyls and the triaryl esters ofphosphorothionic acid.

We claim as our invention:

1. A lubricating oil composition comprising a major proportion of a baselubricating oil and from 0.1 to 10% by weight of a diaryl haloalkylphosphate of the formula wherein R is monoto di-nuclear aryl which issubstituted with from to alkyl groups having 1 to carbon atoms; X is achalcogen having an atomic number of from 8 to 16; R is nonto di-alkylmethylene, where alkyl has 1 to 4 carbon atoms; n is an integer from 1to 6; Y is nonto per-chloroalkyl having 1 to 2 carbon atoms; and Z ismonoto tri-chloromethyl.

2. The composition of claim 1 wherein R is phenyl, R' is methylene, andn is 1.

3. The composition of claim 1 wherein X is oxygen.

4. The composition of claim 1 wherein X is sulfur.

5. A lubricating oil composition comprising a major proportion of asynthetic lubricating oil base and from 0.1 to 10% by weight of a diarylhaloalkyl phosphate of the formula wherein R is monoto di-nuclear arylwhich is substituted with from 0 to 5 alkyl groups having 1 to 10 carbonatoms; X is a chalcogen having an atomic number of from 8 to 16; R isnonto di-alkyl methylene, where alkyl has 1 to 4 carbon atoms; n is aninteger from 1 to 6; Y is nonto per-chloroalkyl having 1 to 2 carbonatoms; and Z is monoto tri-chloromethyl.

6. The composition of claim 5 wherein the synthetic lubricating oil baseis the aliphatic diester of dibasic carboxylic acids having from 6 to 20carbon atoms and monohydric alcohols having from 1 to 12 carbon atoms.

7. A synthetic lubricating oil composition having improvedextreme-pressure properties which comprises a major proportion of asynthetic ester base and from 0.1 to 10% by weight of a diaryl haloalkylphosphate of the formula wherein R is monoto di-nuclear aryl substitutedwith from 0 to 2 alkyl groups, alkyl having from 1 to 10 carbon atoms; Xis a chalcogen having an atomic number from 8 to 16; Y is nontoper-chloroalkyl having 1 to 2 carbon atoms; and Z is monototri-chloromethyl.

8. The composition of claim 7 wherein R is phenyl.

9. A lubricating oil composition comprising a major proportion of asynthetic ester lubricating oil base and from 0.1 to 10% of a diarylhaloalkylphosphate selected from the group consisting ofdiphenyl-2,2-bis(chloromethyl)-3-chloropropyl phosphate;diphenyl-2,2-bis(chloromethyl)-3-chloropropyl phosphor-othionate;dioctylphenyl-2,2-bis chloromethyl) -3 -chloropropyl phosphate; anddioctylphenyl-2,2-bis chlorornethyl) -3 -chloropropyl phosphorothionate.

10. The composition of claim 4 containing anantioxidant selected fromthe group consisting of 2,6-ditertiarybutyl-4-methyl phenol;4,4'-methylene bis(2,6-ditertiarybutyl phenol);phenyl-alpha-naphthylarnine; phenyl-betanaphthylarnine;2,2'-dipyridylamine; and diphenylamine.

References Cited by the Examiner UNITED STATES PATENTS 2,289,509 7/ 1942Malisofl 25249.9 2,656,373 10/1953 Gamrath 260965 2,758,091 8/1956Webber 25249.9 2,760,937 8/1956 McDermott 25246.7 3,218,256 11/1965Edwards et a1. 25247.5

DANIEL E. WYMAN, Primary Examiner.

L. G. XIARHOS, Assistant Examiner.

1. A LUBRICATING OIL COMPOSITION COMPRISING A MAJOR PROPORTION OF A BASELUBRICATING OIL AND FROMM 0.1 TO 10% BY WEIGHT OF A DIARYL HALOALKYLPHOSPHATE OF THE FORMULA